The present invention relates in general to integration of multiple different zones into a honeycomb extrusion monolith-based chemical reactor and methods to achieve such, and in particular to multiple zones in a honeycomb monolith reactor that provide distinct functions such as integrated and zoned separation or heat exchange, and to methods for making such reactors.
Techniques for fabricating low-cost continuous flow chemical reactors based on extruded honeycomb monoliths have been presented previously by the present inventors and/or their colleagues, for example, as disclosed in EPO Publication No. 2098285, assigned to the present assignee. With reference to FIG. 1, which is a perspective cut-away view of such a device, in a reactor 10 of this type formed within a monolith substrate 18, fluid flows in millimeter-scale channels 22, 24. At least one fluid path 28 is formed, typically having periodic U-bends created by machining end face regions of the reactor substrate 18 and then selectively plugging channels 24 with plugs or plugging material 26, as shown in the figure. This approach allows long, large volume serpentine fluid passages such as passage or path 28, useful for process fluids, to be formed within channels 24 closed by the plugs or plugging material 26, with many millimeter-scale open channels 22 adjacent to the channel(s) 24 containing path 28, useful for flowing heat exchange fluid 30 through. Alternatively, reactant may flow parallel to the extrusion direction in the short straight channels 22, while heat exchange fluid flows through the path 28. The first of these two configurations is generally preferred where longer residence times or higher heat exchange is required. As shown in the cross-sectional view of a similar reactor 10 in FIG. 2, with the cross-section taken through the channels closed by plugs 26 or plugging material 26 and containing the path 28, the path 28, which is typically the process fluid path, need not be limited to following a single channel of the monolith substrate 18 at a time, but can follow groups 25 of two or more channels in parallel (with groups 25 of two shown in this case), with U-bends 29 allowing flow from one group of the next. As shown in the cross-sectional view of a similar reactor 10 in FIG. 3, with the cross-section again taken through the channels closed by plugs 26 or plugging material 26 and containing the path 28, the path 28 need not follow the original direction of the channels of the substrate 18 at all, but may pass in a direction perpendicular to the channels of the substrate without the need of U-bends in the path 28. Such a structure may be provided by deep machining of alternate walls of the cells of the substrate 18 followed by plugging with plugs 26 or plugging material 26, such as disclosed and described by the present inventor and/or colleagues in U.S. Pat. Publication No. 20100135873, assigned to the present assignee.
The present disclosure aims to add to the range of application of reactors of this type by providing individually controlled and/or tailored zones within a single monolith for improved reaction performance.